1. You can add to your core a routable ip. When open your browser from the phone and go to http://<your_ip_address>/pluto-admin/check.wml.

2. If you don't want to add a routable ip to the core, you will need to use another linux machine which has one. There, you'll have to create a file "check.wml" which uses 'curl' to access the wap page from the core: